Summary. Labetalol was compared with methyldopa in a randomized controlled trial involving 176 pregnant women with mild to moderate hypertension. Diastolic blood pressure below 86 mmHg was obtained in a similar proportion of women given labetalol or methyldopa. Intrauterine death occurred in four women treated with methyldopa, and the one neonatal death on day 1 occurred in the labetalol group. The average birthweight and the proportion of preterm or small‐for‐gestational‐age babies were similar in both groups. Heart rate, blood pressure, blood glucose, respiratory rate, and Silverman score of the babies did not differ between the two treatment groups, whether the comparison was made for all the infants, or only for those that were preterm or small‐for‐gestational‐age. These data indicate that maternal betablockade with labetalol is as safe as methyldopa for the fetus and the newborn.

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Immunoassayable plasma renin activity (PRA) was measured in 16 healthy preterm infants of different gestational ages. A total of 52 measurements have been performed between the second week of life and the date of the expected term. PRA was found markedly increased in preterm infants and a highly significative negative correlation with postmenstrual age was proved.

Functional residual capacity (FRC) variations in relation to sleep state changes were studied in 11 premature infants with birth weights of 1.68 ± 0.48 kg and gestational ages of 32.7 ± 2.2 weeks (mean ± SD). Helium dilution was used to measure FRC, and sleep states were identified using neurophysiologic criteria. No significant difference in FRC could be demonstrated between data collected during active sleep (AS) and quiet sleep. However a relationship was shown between AS and paradoxical breathing (p < 0.02) and between AS and irregular breathing (p < 0.05). Several factors are discussed which might explain the discrepancy between the present data in premature infants and the previously published data in term infants. (1) Neurophysiologic identification of sleep states does not include breathing pattern whereas behavioral identification does. It is therefore possible that lung volume changes are related to breathing pattern changes and not to sleep state changes per se. (2) Maturational changes may occur among the mechanisms which control FRC, leading to a progressive stabilisation of FRC, the variation of which could become related to sleep state changes.

P e d i a t r i c s , Oregon Health Sciences Univ., P o r t l a n d , OR. Moment a n a l y s i s (MA) of MBNW could i n theory be a good method o f q u a n t i f y i n g v e n t i l a t i o n inhomogeneity i n young c h i l d r e n s i n c e i t r e q u i r e s only q u i e t b r e a t h i n g of oxygen f o r <2 minutes and t h e r e s u l t s a r e independent of b r e a t h i n g p a t t e r n o r lung volume. We have developed t h e software r e q u i r e d f o r on-line MA of MBNW and have performed d u p l i c a t e s t u d i e s on 36 h e a l t h y c h i l d r e n (H) and 10 w i t h c y s t i c f i b r o s i s (CF) ages 3-6 y e a r s . Outcome v a r i a b l e s included FRC, moments 0 , 1 , 2 and moment r a t i o s Mi/% and M2/% I n H t h e r e were no s e x r e l a t e d d i f f e r e n c e s i n FRC o r moment r a t i o s w h i l e a b s o l u t e moments tended t o be h i g h e r i n boys (p<.05,MO). Int r a s u b j e c t c o e f f i c i e n t of v a r i a t i o n (CV%) was < l o % f o r a l l v a r ia b l e s . I n t e r s u b j e c t CV% f o r M1/%=8%, M2/%=13%, and FRC=18%. A modified Shwachman (S) s c o r e was used t o q u a n t i f y lung involvement i n CF w i t h a s c o r e o f 75 being t h e b e s t p o s s i b l e . The CF group v a r i e d from no lung involvement t o s e v e r e d i s e a s e , S s c o r e 30-75. Mean FRC was no d i f f e r e n t i n CF v s H while mean M1/M0 and M2/% were b o t h higher i n CF, 2.59 v s 2.32 and 13.04 v s 9.31, p< .001. 7 of 1 0 CF had moment r a t i o s >95th p e r c e n t i l e of H. The 3 w i t h v a l u e s i n t h e normal range had higher S s c o r e s than t h e 7 w i t h abnormal v a l u e s , mean 65 v s 47, p<.001. Moment r a t i o s i n CF showed a good c o r r e l a t i o n w i t h S s c o r e s ; f o r i n s t a n c e Ml/%=3.35 -.01.S s c o r e r=.67, pC.01. We conclude t h a t MA of MBNW has promise a s a t e s t of lung f u n c t i o n i n young c h i l d r e n s i n c e t h e method is non-invasive, low i n v a r i a b i l i t y , and appears t o have t h e s e n s i t i v i t y r e q u i r e d t o d e t e c t mild v e n t i l a t i o n inhomogeneity. During behavioural a c t i v e s l e e p (AS) a s compared t o q u i e t s l e e p ( Q S ) , a 30.z decrease i n lung volume has been r e p o r t e d i n term newborns. T h i s study was designed t o determine whether such changes i n lung volume a r e r e l a t e d t o changes i n s l e e p s t a t e s o r t o changes i n b r e a t h i n g p a t t e r n . The r o l e o f maturation was a l s o a ss e s s e d . We used t h e helium d i l u t i o n method t o measure FRC. Neurophysiologic c r i t e r i a were used t o i d e n t i f y s l e e p s t a t e s . Movements of c h e s t and abdomen were monitored.Results (1 _+ SD; FRC= o f -t h e i e 26 newborn i n f a n t s , FRC happened to-be meastked when b r e a t h i n g showed two completely o p p o s i t e p a t t e r n s : OUT o f phase and IN-phase b r e a t h i n g . FRC "OUT" (1.38 +_ 0.25 ml/cm) was lower than FRC "IN" (1.56 t 0.25 ml/cm...